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STATE PLANT BOARD 

July 1953 E-860 



United States Department of Agriculture 

Agricultural Research Administration 

Bureau of Entomology and Plant Quarantine 



TESTS OF INSECTICIDES FOR GRASSHOPPER 

CONTROL--195C, 1951, and 19521' 

By O. L. Barnes, F. T. Cowan, E. 1., Hinman, 
N. J. Nerney, and Lee Seaton— 
Division of Cereal and Forage Insect Investigations 



Tests of insecticides for grasshopper control have been reported in 
previous publications of this series—tests in 1946 (E-722), in 1947 
(E-774), and in 1948 and 1949 (E-807). This paper presents the results 
of similar tests made in 1950, 1951, and 1952. They should not be con- 
strued as recommendations of the insecticides for general use. Insecti- 
cides are more or less toxic to warm-blooded animals and therefore 
should be used with suitable precaution. 

SPRAYS 

Objectives 

In 1950 the main objective was to obtain more information on aldrin 
and to establish minimum effective dosages of this insecticide. Tests 
were planned to compare various dosages applied in solutions or 
emulsions on small plots with ground equipment and on large plots with 
aircraft. The effectiveness of aldrin at different seasons and under 
different crop conditions was given particular attention. Other objectives 
were to make preliminary tests of dieldrin, heptachlor, compound 1189 
(2,3,3a,4,5,6,7,7a,8,8-decachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene 
1-one), CS-708 (Dilan), lindane, and methoxychlor. 

In 1951 the main objective was to determine minimum effective 
dosages of dieldrin and heptachlor and to obtain more data on the mini- 
mum effective dosage of aldrin. The effectiveness of these insecticides 



1/ The Division of Grasshopper Control furnished some of the in- 
secticides and equipment, and assisted in some of the tests. 

2/ O. L. Barnes and N. J. Nerney are located at Tempe, Ariz., 
and the other authors at Bozeman, Mont. 






under different seasonal il attention. 

ing of compound 1 189 and 
h toxicants had s siderable promise in 1950. 

j n is to contin .{ of minimum 

sages of heptaehlor and to establish an ef: ge of 

Ex. <-ntal Conditions and Methods 

M< era of the Laboratories at Tempe, Anz., and Bozen. M 
co< tests in Arizona during the s of 

ibji, di, ~. Tests pes: .zona 

♦he summers of 1950 and 1951 and by the Bozeman s 

mers. 
In Arizona tests . nade in short to medium (1-14 inches) 

ga - 50, 1951, and 1952, and in sparse range grass also 

1950. The dominant species of grasshoppers in the alfalfa wi 

xs (Sauss.) and M. (Thos. 

unda; 4e 

grass. The the short, greei 

ag Digitized by the Internet Archive 

ss in both 1 ' ••. r\r\A r\ 

vdb.)) and blue grama (Boir Jn2013 (H. B. K.) Lag.) pi 
in both Montana areas. 

In 1950 twelve species of grasshop; 
grass plots in southeastern Moi of them--D_ 

I.). A^ 
MJ linus (! ,), i Phlib>'s;:-onv. 

38 percent of the total pop 

north-< entr F 

lliotti (Thos.), M. iraxu anus , A. 
An.phitnrnus . .■! w.kIw:, ( Tho he to- 

ri. 

ired solutioi ails if: 

A: m the ground 

■ 

http://archive.org/details/teconhopinci00unit 



- 3 



The results of the tests of ground applications were evaluated by the 
sweep-net method described in E-722. The results of all airplane tests 
were evaluated by calculating a straight reduction in populations by sweep- 
net samples before and 3 and 5 days after treatment. Population reduc- 
tions were also determined by the pointer method, which consisted in 
counting the grasshoppers from a unit area of 1 square foot to 1/2 square 
yard depending on populations. A light metal or bamboo rod 6 to 8 feet 
long, held by the operator, was used to excite the grasshoppers and 
cause them to jump. Counts were made as the grasshoppers jumped off 
the unit area. From 25 to 50 samples were taken on each plot before 
and after treatment, and the reduction in population, or the percentage 
kill, was calculated. 

The results of tests in Arizona and Montana in 1950 and 1951 on 
alfalfa and range grass, and in Arizona in 1952 on alfalfa, with the 
various insecticides are given in tables 1 to 6. Weighted averages 
have been used. 

Aldrin 

In 102 trials in which aldrin was applied at 2 ounces per acre, the 
average mortality after 3-4 days was 87 percent. This included 18 
applications by airplane on 40 -acre plots and 84 by turbine blower on 
plots of 1 1/4, 2 1/2, and 5 acres. In 8 trials by airplane 1.5 ounces 
gave an average kill of 85 percent. In 73 trials, 6 of which were by 
airplane, 1 ounce gave an average kill of 79 percent. In 15 trials 0.5 
ounce gave 74-percent kill. Three ounces in 9 trials gave a kill of 
97 percent. 

These data show little difference between dosages of 1.5 and 2 
ounces per acre. In the 1950 airplane tests in Montana, where both 
dosages were used, the difference was somewhat greater. The 2-ounce 
dosage gave an average kill of 81 percent and the 1.5-ounce dosage 85 
percent. After 5-7 days the 2-ounce dosage averaged 88 percent and 
the 1.5-ounce dosage 83 percent. At the end of the test the respective 
populations, measured by the pointer method, were 0.9 and 1.8 grass- 
hoppers per square yard. 

Dosages of 1 and 2 ounces per acre were compared in green to dry 
alfalfa in Arizona. In green alfalfa 1 ounce gave an average kill after 3-4 
days of 88 percent in 17 trials. Two ounces was slightly better at 91 per- 
cent in the same number of trials. In 14 trials with each dosage in dry- 
ing alfalfa the kills were slightly higher and in about the same proportion. 
One ounce killed an average of 89 percent and 2 ounces 93 percent. In 
dry alfalfa both dosages were less effective. In 13 trials 1 ounce dropped 
to 64 percent and 2 ounces to 72 percent. 

On range land in Montana no attempt was made to separate results 
obtained under different conditions of dryness, but slightly higher results 
were obtained in stands of grass that were above average in density and 
succulence. 






I isons n emulsions and solutions 

e data. Ii si ounce in emulsio: 

ve an average kill of 81 percent. In 10 trials 1 ounce in solut; 
1 gallon ere gave kill of 80 percent. I: isions 

ces gave an average kill of 85 p. ■ ■ in 58 trials, 6 of wr. re 

made under hot, dry c I wo ounces in solutions in 

• ige kill of 90 perc- .Is, 12 of which were inder conditions 

of s. In one • ent in which both formulations were 

I, 2 our solutions gave an average ki! 'J percent n 

trials. In 6 trials with emulsions under the same conditions, the kill 
-> only -cent. 

A comparison of applications made by turbine blower and 1 
craft at 1 and 2 ounces per acre showed little difference in the average 
kill. In 141 trials with the turbine blower the average kill was 83 p- 

•. In 34 trials by aircraft the average was 85 percent. In 107 trials 
of emulsion I lrbine blower at 1 and 1.6 gallons per acre tl rage 

kill was 84 percent and of solutions 8! in 26 trials. In 10 trials 

of emulsions by aircraft at 1 gallon per acre the average kill v 

ent compared with Ml percent in 20 trials for solutions at the sai 
te per acre. When solutions were applied b illon 

per acre the average kill was 82 percent in 12 trials. I 
cho • tween formulations where heighl of flight was 15 feet or less. 

In high flights (50 to 7.") feet) the emulsions were less effective th 
oil solutions, and 0.5 gallon per acre was also less * . e than 1 gallon. 

L.^ ' yum < : I at urns . --In 1950 5,000 

res of Land in Mo: tnd Wyomii h 2 ou 

aldrin in 1 gallon oi 

horsepc .s 

use il tests. This plane COUld be calibv - 1 

• In 50- or 7 • strips, 

-t of the 

. C.wdillacriS oeeipital: . , d U 

A. deorum, A. coloi M. pard . I | .), nd 

50 

per squ i I the plot 

■ 

flight tall, Lush > ra- 

..... 

In more I 

I .unl .'. 

! . I . 



-5- 



Sprays were applied by 7 commercial and 1 Bureau-owned aircraft. 
Aldrin dissolved in kerosene was used at 2 ounces in 0.5 or 1 gallon of 
spray per acre. Flights were at low altitude, under 20 feet, except 
once or twice, when the pilots were forced to 50 feet or higher by rough 
terrain or trees. The sprays were applied in 50-foot strips. 

Kills in 3 days ranged from 67 to 99 percent, with an average of 91 
percent for 11 observation stations. Kills in 5 days were higher, with 
an overall average of 97 percent. Population estimates 5 days after 
treatment showed 1.25 grasshoppers per square yard. One small area 
where high airplane flight was necessary showed only partial control 
and was resprayed. Results with 0.5 and 1 gallon of spray were almost 
identical. 

Twenty-five species of grasshoppers were recorded from the sprayed 
area. Eighty-three percent of the total were M. lakinus , B. nubilum , 
Psoloessa texana pusilla (Scudd.), and Phoetaliotes nebrascensis (Thos.). 
Brachystola magna (Gir.) was also present in large numbers. Visual 
estimates of population density before treatment ranged from 12 to 50 
and averaged 22.5 per square yard. 

Dieldrin 

In 1950 dieldrin was tested at dosages of 1, 2, and 3 ounces per acre 
in Arizona. In 18 trials at 1 ounce the average kill after 3-4 days was 
95 percent and in the same number of trials at 2 ounces 97 percent. 
Three ounces gave an average kill of 99 percent in 7 trials. Because 
all three dosages gave approximately the same kill the two higher ones 
were not tested further. 

In 59 trials including applications in alfalfa and range grass by air- 
craft and turbine blower, 1 ounce per acre gave an average kill after 
3-4 days of 93 percent; at 0.75 ounce the average kill was 92 percent 
in 43 trials; and at 0.5 ounce it was 93 percent in 20 trials. There was 
no difference between the average kills of the three dosages. 

Dosages of 0.75 and 1 ounce per acre were compared in green to 
dry alfalfa in Arizona. In green alfalfa 0.75 ounce gave an average 
kill of 97 percent in 8 trials and 1 ounce 95 percent in 15 trials. In 
drying alfalfa the average kill for 0.75 ounce in 7 trials was 96 percent 
and for 1 ounce 97 percent in 13 trials. In dry alfalfa at higher temper- 
atures the 0.75-ounce dosage gave only 65-percent kill in 6 trials. The 
kill from the 1 -ounce dosage was also much lower, averaging 83 per- 
cent in 11 trials. A dosage of 0.5 ounce was not tested under dry, hot 
conditions in Arizona. Emulsions were used in all of the tests on alfalfa. 

In range lands in Montana all three dosages--l, 0.75, and 0.5 ounce 
per acre- -gave average kills of 95 percent or better when applied in 
solutions by turbine blower or aircraft. The application by turbine 
blower gave slightly lower kills than those by aircraft. 






\) . utions were not p< 

sib;. >ns w« included 

in • s. In ar. 11 comparison in which 

, , nd method of appli solutions 

o slightly higher kills. At 0.5 ounce per acr< e was 

unce Uthough 

se di: do inc: I solutions might 

Id a higher kill th s. 

H< | • •.< hlor 

I: 19 >0 tests were made with an emulsifiable concentrate con* 
42 percent of t< the material sup- 

plii facturer for testing was an emulsifiable concentrate 

ercent of a | t reported to be 70 percent heptachlor 

and < hlordane ison.< r . 1 • ounds of technical heptachlor 

lion was guaranteed. Because of this change in the basic formu- 
• results of • not directly comparable with 

In 1951 and 19 r . . 
;n 28 trials of I hlor applied at 1 ounce pel 

fa and range grass th ill after 3-4 da 

losage in the same number of trials ga 
kill of B< 3-ounce dos 

t. All dosages showed a tender rer kills in dry alfalfa 

under higher temperatures later in the seas. OS on i 

kills ent below the . for dos- 

ages of 1 and 2 ounces. 

In 1951 dosages i 
emulsion ed in alfali • : 

kills of HO :.t, 6 oun> 

tncea nt. In l 

. . kJl I •. In 7 Of thl IS, whirl to 

Ifalfa • l11 throe dov 

,. kill Iry alfalfi 

4-ouj 

kil '■ M ounv 

4 -ounce d. 

s. 

■■• 

: A 

I I 

( ind 1 1 8 



- 7- 



separated. In 1951 tests in alfalfa were made with an emulsion. Appli- 
cations by turbine blower on range land in Montana were made with an 
emulsion in 1950 and a solution in 1951. 

In a total of 22 trials in which compound 1189 was applied at 0.5 
pound per acre the average kill after 3-4 days was 78 percent. In 45 
trials at 0.75 pound per acre the average kill was 86 percent, and in 
22 trials at 1 pound 87 percent. Kills 5-7 days after application were 
3, 5, and 4 percent higher for dosages of 0.5, 0.75, and 1 pound. 

In green alfalfa at cool temperatures 0.5 pound per acre yielded an 
average kill after 3-4 days in 15 trials of 80 percent compared with 88 
percent in 8 trials at 0.75 pound per acre. Kills after 5-7 days were 
slightly lower. In drying alfalfa under moderate conditions in late 
spring 0.75 pound gave 78-percent kill in 13 trials compared to 81 per- 
cent for the 1 -pound dosage in the same number of trials. Mortalities 
after 5-7 days were 12 percent higher for the 0.75-pound and 11 percent 
higher for the 1 -pound dosage. In dry alfalfa under high temperatures 
of midsummer both dosages killed 94 percent of the grasshoppers after 
3-4 days. Mortalities in 5-7 days were slightly lower. 

Dosages of 0.5 pound per acre in solution applied to range grass 
killed 75 percent of the grasshoppers after 3-4 days and 88 percent 
after 5-7 days. In 15 trials on range land, 7 of solution and 8 of 
emulsion, 0.75 pound killed 87 percent after 3-4 days and 92 percent 
after 5-7 days. 

CS-708 

Preliminary tests with CS-708 were made in Arizona and Montana 
in 1950. Dosages of 0.75 and 1 pound per acre were applied in emulsion 
in alfalfa in April, July, and September and compared with a standard 
spray treatment of 1 pound of chlordane per acre. In the early and mid- 
season tests 0.75 pound of CS-708 yielded results 6 and 24 percent lower 
than the standard. When it was applied at 1 pound per acre in late 
season, the average kill was only 2 percent under that of the standard. 
In 8 trials on range land in Montana 0.75 pound averaged 4 percent less 
than the chlordane application. 

Dosages of 0.5 and 0.75 pound per acre were tested in direct com- 
parisons in Arizona and Montana in 1951. In 15 trials, 8 of emulsion 
and 7 of solution, the 0.5-pound dosage averaged 89-percent kill after 
3-4 days. The 0.75-pound dosage averaged 92 percent in the same 
number of trials. These tests were made in green alfalfa in Arizona 
and on range land in Montana. In 13 trials in drying and dry alfalfa in 
Arizona the 0.75 -pound dosage averaged 79 -percent kill and the 1 -pound 
dosage 80 percent. 

The results of these experiments are not sharply defined and the 
small difference in kill might easily be accounted for through 

library 

OTAT E PLANT BOARD 



8 - 



that CS-708 is more toxic to 
■ es in green alfalfa than it is under 
high t- rid dry alfalfa. The kills after 

: ys thl ut all of th«- te tly under those 

I days, indicating .d drop in residual action. 

Lindane 

In 1!>50 lindane emulsion was applied by turbine b. .o alfalfa 

in Arizona at 0.5, 0.75, and 1 pound \ ■ e. 

The average kill after 3-4 days in 5 trials for the 0.5-pound dosage 
t under cool temperatures in April. This decreased to 
75 percent during hi: mperatures in July. In 6 trials during J 

ere a direct comparison between 0.5- and 0.75-pound dosages is 
possible, there was little difference between the kills afte: s. 

I -mparisons of 0.75- and 1-pound dosages under hot, d: editions 

m S iber show the 1 -pound dosage to be superior, but the number 

rials is too small to draw definite conclusions. The average kill 
from range-land applications in Montana at 0.4 pound per acre und< 
relatively cool conditions was 2 percent higher than that from the 
standard 1 -pound application of chlordar.' . 

In all of these tests lindane showed a tend- . ard reduced 

toxicity under higher temperatures. There was little or no evident 
of residual kill. 

Methoxychlor 

blor in emulsion A by turbine blower to green 

llfa in April and to drying alfalfa in July. Tl ound dosage g.. 

ge kill af- I days of 7 .t low. n the standard 

chlor : rid per acre, 

I. In late Septeml 

Lfalfa ad 

nt. M 

• burning of alfalfa 

a limited man: nd 

tit. 

El 

. 
■ 

ent kill. 



-9- 



POISON BAITS 

Tests with poison baits for grasshopper control were continued in 
1950 with the emphasis on dry baits for use on range lands with aircraft 
application. With the development and increased use of sprays to con- 
trol crop grasshoppers since 1946, bait usage has decreased rapidly. 
Bait was still being used in 1950 in range grasshopper control, but 
emphasis was changed to sprays late in the season. No bait was used 
on range land in 1951 with the exception of a small quantity against 
Melanoplus rugglesi Gurney in Nevada and California. 

No further work with baits is anticipated, except possibly for range 
grasshopper control in high mountain valleys, where trees and rough 
terrain might hinder low flights necessary in spraying, and for the 
protection of newly seeded winter wheat. 

Objectives 

In Arizona the main objectives were to compare chlordane, aldrin, 
dieldrin, and heptachlor in various dosages as bait toxicants, and to 
compare baits containing aldrin in different concentrations, at different 
rates per acre, and applied both wet and dry. The effectiveness of dry 
baits containing chlordane on range grasshoppers was given particular 
attention. 

In Montana the main objective was to test two new materials, pear 
pomace and orange meal, as carriers for the toxic agents in dry baits. 

Experimental Conditions and Methods 

All tests in Arizona were made by members of the Tempe laboratory, 
Most of the experimental plots were in irrigated alfalfa ranging from 4 
to 36 inches high and from green to dry. Plot sizes were 1 l/4 acres in 
alfalfa, with one series in range grass on 5-acre plots. M. mexicanus 
and M. differentialis were the dominant grasshoppers in the alfalfa. 
B. nubilum , M. lakinus , and M. regalis (Dodge) predominated in the 
range grass. 

All dry baits were prepared by dissolving the desired quantity of 
the toxic agent in 0.5 gallon of kerosene or fuel oil, and spraying this 
solution on 100 pounds of coarse, flaky bran. Applications of dry baits 
were made with the turbine blower. Wet bait was applied with a power- 
operated bait broadcaster. Kills were evaluated by the same method 
used in tests of sprays. 

Further tests were conducted on range lands in southeastern 
Montana by members of the Bozeman staff. Applications were made 
with the turbine blower on 10- and 40-acre plots. A. deorum , A_. 
coloradus, P. quad rimacu latum , O. obscura , and M. mexicanus were 
the most abundant species. 



10 



I .sts in Ariz< 

!'•■:.■ •.' :■ differ*w.t ■ <.r.. > r.- rati; :. . Baits containing 4 and 8 
oui • I chloi rid 2 oun< es of aldrin, dieldnn, and hepta- 

- hlor per 100 pounds ol • d by turbine bl it 5 pounds 

p« n alfalfa during Ma} and June and • een to drying 

ring July and Augi. 
Kills with baits <■ Lng aldrin, dieldnn, and heptachloi • -re 

similar in 3 days, ranging from 65 I cent. With rhlordane bait 

the kills ranged from 59 to 62 { I - . Aldrin, dieldnn, and rhlordane 

•s continued to kill for 6 to 7 days, and the final reduction was 10 to 
12 | nt higher than on the third day after treatment. Heptachlor 

was least consistent in its residual effect. In all tests in green to 
drying alfalfa grasshopper mortalities were approximately 10 percent 
greater during July and August than in earlier tests. The lower dosage 
of chlordane, aldrin, and heptachlor § 3-day kills than the 

higher dosage. This might suggest that the higher dosages were not so 
ible as the lower ones. After 6-7 days the kills about equal 

with the low and high dosages. 

Aldrin wet and dry baits and chlordam- d • -. : ,■.:•..- .-.- :,• • 
centi I dosages . —A I Lning 2 ounces of aldrin per 100 

pounds of bran was applied dry at 5 and 10 pounds per acre. Wet b 
with the same amount of aldrin was prepared with both sawdust and 
:i and spread at 20 and 40 pounds per acre. Bait containing 1 out 
• 100 pounds of carrii nd 10 

inds | • re, and bail containing 8 ounces of chlordane at 10 pounds 

The a. • kills after 3 d r dry baits pi ou: 

ildrin at 10 ] I for w< I mtaining 2 - of 

aldrin al 40 pounds per acre, were 
nts the kills rai i 52 to 61 

aldrin nd B ounces of chlor I is 

the lowest e kills. I the 

kills from all baits excrpt the one containing 1 ounce oi aldrin at 5 

... re had i d approximately 14 pei ".al 

: 7u to 79 • ent. l hei an 

d drj 

D ry I'ait containing chhwdane mi range laiul . --A c 

h oun. ei of chlordane per loo pounds of i • 

at Id poui " • 

• . : • e kill ; I : 

A 

ning l 
1 1 In . 



11 - 



Tests in Montana 

Two new carrier materials were tested in a single trial on range 
land in southeastern Montana. One of them was pear pomace milled to 
such fineness that 65 percent passed through an 8-mesh screen and 23 
percent a 20-mesh screen. The other one was finely ground orange 
meal. Both carriers were treated with 2 ounces of aldrin dissolved in 
2 quarts of No. 1 fuel oil per 100 pounds of the carrier, and the bait 
was applied dry. A dry bran bait containing the same toxic agent was 
included for comparison. Applications were made with a turbine blower 
on 10- and 40-acre plots. 

The bait made with pear pomace gave 62-percent kill in 3 days and 
65 percent in 5 days; orange-meal bait gave kills of 38 and 41 percent; 
and dry bran bait gave kills of 47 and 54 percent. In this test pear 
pomace was definitely superior to either orange meal or bran as a 
carrier. It was apparently more palatable than orange meal and more 
attractive than bran, even to those species of grasshoppers that normally 
do not accept poison bait. However, none of the baits approached the 
control efficiency obtained with the better toxicants applied as sprays. 

SUMMARY 

Tests to determine minimum effective dosages of various insecti- 
cides in sprays and baits for grasshopper control were continued in 
1950, 1951, and 1952. 

Aldrin at 0.5 ounce per acre was unsatisfactory. A dosage of 1 
ounce gave satisfactory kills only in short, green to drying alfalfa. 
At the time of application, the grasshoppers were young. Two ounces 
was generally satisfactory. Both 1- and 2-ounce dosages gave better 
results in solutions than in emulsions. The kill with emulsions was 
generally lowest in very dry and hot weather. In aircraft applications 
the kill decreased when the plane was forced to fly above 15 to 20 feet. 
There was little difference between 0.5 and 1 gallon per acre of oil 
solutions containing 2 ounces of aldrin when applied by aircraft. 

Dieldrin in emulsion tested at dosages of 1, 2, and 3 ounces per 
acre in 1950 showed little difference in the average kills. In 1951 
ground applications of 0.5, 0.75, and 1 ounce in emulsion and oil 
solution gave about the same average mortality- -92 percent. Kills 
from aircraft applications on range were 97 to 99 percent. The 0.75- 
and 1 -ounce dosages in emulsion did not give satisfactory kills in dry 
alfalfa at high temperatures in Arizona. 

Heptachlor gave satisfactory kills at dosages of 1, 2, 3, 4, 6, and 
8 ounces per acre in green to drying alfalfa under cool temperatures. 
The two lowest dosages were unsatisfactory in drying to dry alfalfa 
under moderate to high temperatures, and the three highest dosages 



-12- 



re un- ry under dry, hot conditions of midsummer. The 

dosage gave highly kills in aircraft appl. . :.s on 

nd. 

Compound 1189 gave satisf :11s at 0.75 and 1 pound per acre, 

rticularly when applied during dry, hot W< showed 

mise of good residual action. 

I 708 a1 B dosage of 0.75 pound per ; ave satisfactory kills in 

green alfalfa, bul • ased in i i m drying and dry alfalfa 

unc hot conditions. 

Lind 0.5 pound per n emulsion was satisfactory in alfalfa 

in early spring tests in Arizona, but was unsatisfa at 0.5 and ( . 

pound under hot, dry conditions in July. The 1 -pound dosage gave satis- 

ory kills in early fall tests on alfalfa in Arizona, as did the 0.4- 
pound dosage in range land in MontaJ 

thoxychlor at 3 pounds per acre in emulsion gave satisfactory 
kills in spi ing tests, but both 3- ar/: mid dosages were unsatis- 

factory under hot, dry conditions in Arizona. Moderate to severe 
burning to alfalfa was noted in the later tests. 

EPN at 6 ounces per acre was satisfactory in spring tests in Arize 
but a 2-ounce dosage in the same tests was unsatisfacto: . 

Baits containing aldrin, dieldrin, and heptachlor at 1 and 2 ounces 
per 100 pounds of bran gave higher kills than baits containing 4 and 8 
ounces of chlordane when spread in green alfalfa in May and June. 
Aldrin, dieldrin, and chlordane baits continued to kill 6 to 7 days. 

sshopper kills from all baits were higher in July and August. Baits 

raining 1 ounce of aldrin per 100 pounds I a kiK to 

75 | t when spread at 10 pounds per acre. At 5 and . >unds the 

kills were somewhat less. There was little difference in the kills 
ned between wet and dry bait. 

In Montana pear pomace and orange meal were test* ra 

for- the toxK ant in comparison with bran in dr; . Pt BJ DBS 

11 gave the highest ige kill, and was apparently mo; 

either bran or tl. 



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